1. Field of the Invention
The field of the invention relates to waterproof outerwear. More particularly, the invention relates to waterproof outerwear made of flexible sheet material, such as elastomeric PVC, polyurethane elastomer, or other thermoplastic alloys, that changes its appearance as the ambient temperature changes.
2. Description of the Prior Art
Conventional waterproof apparel, which includes raincoats or jackets, rain hats, rain pants and footwear, is generally constructed of a waterproof material. The types of material used for such waterproof apparel include woven and non-woven material, material that is inherently waterproof, such as PVC or other polymeric extruded or calendered sheet material, as well as woven cotton material that is surface-treated with a waterproofing coating.
Essentially, the purpose of waterproof apparel is to protect the wearer from the external elements. Many types of material are already known that satisfy this purpose adequately. It is also important that waterproof apparel be comfortable to wear and aethetically pleasing and it is in this area that waterproof apparel is often less than satisfactory, particularly for children. Children often refuse to wear traditional waterproof apparel because it is found to be cumbersome and unappealing. Thus, children are often exposed to undesirable weather elements without benefit of protective clothing.
It is, therefore, desirable to provide waterproof apparel that provides an entertaining and surprising effect that is appealing to children. One such entertaining and surprising effect is to provide for a color change in the fabric of the waterproof apparel, depending on the temperature or on sunshine. It is know to effect a change in the color of a material by the use of thermochromic dyes or inks.
Thermochromic dyes allow a reversible color change as a function of temperature change. For instance, a thermochromic dye incorporated into a material appears transparent until the material reaches a certain temperature, at which time, due to an electron exchange, the color pigment of the thermochromic dye is released from encapsulation and the material takes on the color of the pigment. Thermochromic materials can be formulated to “change” color when the temperature rises above or falls below a predefined temperature.
Thermochromic dyes and their use in PVC sheet material are known. The Pilot Ink Co. teaches thermochromic dyes and methods of incorporating them into plastic materials. See, for example, Nakasuji et al. (U.S. Pat. No. 4,028,118; 1977) and Kito, et al (U.S. Pat. No. 4,421,560; 1983), which disclose thermochromic sheets comprising a thermochromic layer containing thermochromic material that is laminated onto a backing material. By using a suitable technique, such as adding the thermochromic material to a polymeric substance, the resulting mixture is then made into a film that can be heat pressed onto the backing material. A protective layer is laminated onto the thermochromic layer to make it weather resistant. The protective layer may be a film of polyvinyl chloride (PVC). These patents are herein incorporated by reference.
Shibahashi et al. (U.S. Pat. No. 5,858,914; 1999) discloses applying thermochromic-dye-containing images to a boot. The boot appears to be a uniform, solid color at room temperature, for example, but when the temperature drops below a pre-defined temperature, the images then become apparent. Doolan (U.S. Pat. No. 6,196,241; 2001) discloses an umbrella having a canopy onto which thermochromic-dye-containing images have been applied. When the temperature of the umbrella fabric drops because of the cooling effect of the rain, the images become visible on the canopy. None of the prior art, however, discloses waterproof apparel that is made of a flexible fabric and that incorporates thermochromic properties and/or ultraviolet-sensitive properties.
What is needed therefore is waterproof apparel that provides adequate protection against the elements of the weather, but that is, at the same time, comfortable to wear. What is further needed is such apparel that is aethetically appealing to the wearer. What is yet further needed is such waterproof apparel that is particularly appealing and entertaining to children.